It is common practice to seal a container with a sheet material, such as paper, a polymeric film, aluminum foil, or a laminate of paper, polymeric film and/or aluminum foil. The use of such seals, in many cases, has been imposed on the packaging industry by FDA regulations, as a protection against product tampering. Such seals provide evidence of product tampering, since they are typically destroyed by the process of removing the seal. It is also common to line the inner surface of container closures with a moderately compressible material, such as a polymeric material, pulp board, or a multilayer laminated combination thereof. When a closure containing the liner material is secured to the finish of a container, such as by applying a torque force to a threaded closure that is engaged with a threaded container finish, the resulting pressure exerted by the closure onto the liner, which is interposed between the closure and the container finish, produces a substantially liquid and/or gas-tight seal. When the closure is removed from the container, the liner remains within the closure. Re-engaging the closure with the container finish re-establishes the seal. Liner materials can utilize a pulp or paper substrate or polymeric materials, such as polyolefin foams or laminated multilayer lining materials comprising a combination of pulp or a polymeric foam along with a polymeric film, metal foil, and the like.
In a typical application, closures for containers are lined with a laminated material having a layer of pulp mounted to a layer of aluminum foil by an intermediate wax layer. Such laminated materials also frequently contain a layer of polymer, such as a polyester film, fixed by an adhesive to the foil, and a layer of sealing material fixed by an adhesive to the polyester film. The laminate is produced and shipped in roll form, which is then cut to the required shape and size, and mounted in a closure with an adhesive or by friction.
In use, the resulting lined closure is torqued onto a container, such as a bottle or jar, which has been filled with a fluid or solid product. Next, the capped container is passed through a high frequency induction heating unit. During induction heating, the aluminum foil is heated to a temperature in excess of about 65° C., generally about 150° C. or greater, which melts the wax in the layer between the pulp and aluminum foil. The melted wax is absorbed by the pulp, causing the pulp to separate from the remainder of the material. The sealing material typically is selected to match the material of construction of the container, and is heat-welded or sealed to the rim of the container (i.e.., the container finish) during induction heating. When a consumer removes the closure from the container, the pulp layer remains in the closure as a liner, leaving the foil, polymer film, and sealing material on the container as an inner seal, to provide evidence of tampering and to prevent leakage and contamination of the container contents during storage and shipment.
A clear, transparent seal is often desirable so that the contents of the container can be viewed through the seal, particularly when an opaque container is used. In some applications, it is also desirable to have a liner with a non-absorbent surface in direct contact with the contents of the container, rather than a paper layer. Such applications include, for example, when the contents of the container includes volatile materials or liquid substances that can be absorbed by the paper.
Modem advertizing and packaging often makes use of promotional materials, such as coupons, sweepstakes, games, and the like, to promote products and services. In many cases, this requires placing the coupon or other promotional material on the exterior of the container, where it is easily removed by individuals who did not purchase the product. This has led some to place coupons inside the product container. When the product is a food or drug item, any coupon that contacts the contents of the container must be printed with an FDA approved ink, or must be sealed in a hermetic pouch, both of which add to the expense of the promotional materials. It would be very useful to be able to place a readily retrievable coupon or other promotional material within a container closure. Some specialized closures have been developed, which have chambers for sealing promotional materials inside the closure itself; however, such specialized closures are expensive and can be complicated to manufacture. Accordingly, there is an ongoing need for ways to conveniently include promotional materials, such as a coupon, within a container closure. There is also an ongoing need for improved container sealing materials that provide functional features such as tamper evidence, preservation of product quality, packaging integrity, and the like.
The present invention provides promotional materials integrated with a container seal, so that the promotional material can be included within the container closure and not in contact with the contents of the container. While container seals are a regulatory requirement for many food and drug applications, the container seals of the present invention turn this regulatory requirement into a marketing asset by integrating useful promotional materials into the container seal. The container seals of the present invention can be used with standard, conventional closures to provide promotional materials such as a coupon within the closure, without need for expensive specialty closures.